WORCESTER — The trial of a Dorchester man accused of soliciting the killing of an assistant district attorney is scheduled to begin this week in federal court.

Pernell Powell, 74, was charged in federal court in August 2011 with trying to hire his cellmate to kill the Worcester assistant district attorney who was prosecuting his drunken driving case in state court.

Mr. Powell allegedly offered to pay $4,000 to a cellmate at the Worcester County Jail and House of Correction to kill the prosecutor, who is not named in court records on file in U.S. District Court in Worcester. He is charged with murder for hire.

The prosecutor in the Worcester Superior Court case was recommending Mr. Powell serve 4 to 6 years in jail for his fifth drunken driving charge.

Records show Mr. Powell was sentenced in the state case in January 2012. Mr. Powell was sentenced to 3 to 4 years in prison after a jury found him guilty of driving under the influence of alcohol or .08 percent.

The federal trial in Mr. Powell's case is slated to begin Tuesday.

The alleged plot by Mr. Powell unraveled when the FBI received a letter from a prisoner at the House of Correction. The prisoner wanted to speak to an agent.

FBI Special Agent Michael E. Dwyer interviewed the prisoner, who told them his former cellmate, Mr. Powell, wanted an assistant district attorney killed, according to the agent's affidavit on file in federal court.

The cellmate agreed to wear a hidden recording device and talk to Mr. Powell about the nefarious plot, records show.

Mr. Powell allegedly offered to pay a $2,000 deposit and another $2,000 when the deed was done. FBI agents tracked money orders allegedly sent on behalf of Mr. Powell to carry out the killing.